Treatment of spinnerets to minimize contamination thereof



Patented on. 4, 1949 2,483,783v

TREATMENT OF SPINNERETS T MINI- IHIZE CONTAMINATION THEREOF James J. Polak, West Asheville, N. 0., assignor to American Enka Corporation, Erika, N. 0., a corporation of Delaware No Drawing. Application January 31, 1943 Serial No. 644,663

The present invention relates to the manufacture of rayon and more particularly to spinnerets used in the production of viscose rayon which are treated to inhibit or minimize the contamination of the orifices of the spinnerets during the spin- 5 In treating the spinnerets with the organening operation. silicon halides, very much the same technical A major problem in the manufacture of viscose procedure should be adopted as that di l s d in rayon is encountered as a result of the containithe Patnode Patent No. 2,306,222. Initially, the nation of the spinnerets through which the spinp e a e thoroughly cl by s i g n ning solution is extruded into the spin bath. 1 strong sulphuric acid baths, neutralized ina weak While this problem has been solved by the use of alkaline bath and finally washed in water and dissolved stable cation-active materials in the dried. The method next involves the contacting spin bath as described and claimed in United of the spinnerets with an organo-silicon halide States Patent No. 2,125,031, issued July 26, 1938, by e posing them to the vapor of, for example, attention has been directed toward solving the a mixture of methyl ili on id i i d problem by covering the spinnerets with very p i p ly of (CH3) Sick; and (CH3)2 SiClz in thin films to thereby inhibit their clogging duraccordance with the disclosure of the Patnode m spinning. U. 5. Patent No. 2,100,581 is dipat t s h e d s s d these mp unds rerected to the provision of a film of wax-like mateact with the water adsorbed at the surface of rials such as ozocerite and ceresine on the spinhe spinneret and a very thin silicone him is denerets. United States Patent No. 2,294,154 dispo ted on the pinneret which is water-repel nt closes a method of treating spinnerets with a and is insoluble in the acid spin bath. After a cation active substance. Although somewhat few seconds of the vapor contact with the Sp satisfactory s lt hav b h i th follownerets, portions thereof will be coated after which ing of the teachings of these last referred to it is preferable to introduce vapors of an alkaline United States patents, their utility in commercial nt. s as ammonia. into t e p es n e of operations is limited due to the temporary nature the spinnerets in order to neutralize an acid of the films. In both cases the film either dises that ay be es nt as a result of the solves or wears oil of the face of the spinnerets reaction of e n -silicon halide. in a relatively short time and therefore the spin- It is not ial hat these cream-silicon nerets have to be replaced and the entire treathalides be u l z in th aseous state as they ment repeated before they can be reused. oi o be applied, f p y rubbing 0 In order to spin viscose through an acid spin Wlpmg the Surfaces of h spinn rets. bath of the order of 10% sulphuric acid and The thus treated spinnerets a e s seq en ly maintain optimum spinning conditions over long embodied on pinn n machines and a viscose periods of t such as several k it i neces. solution is extruded through the spinnerets into sary to reduce the involuntary spinneret change an acid spin o h treatment being for the to a, minimum, lnvemnter spinneret h purpose of causing the spinneret to remain clean means the replacement of spinnerets necessary and to avoid the partial total Closing of the as a result of their becoming fouled and the miorifices v n ov r p l nged periods of spinnin nute openings therein becoming totally or parsuch as several weeks. Therefore, the spinnerets tially clogged with impurities occurring in the d o have to be changed except per odic y system, including precipitated cellulose, sulphur when voluntary changes are made at the time deposits, secondary reaction products and the the spinning machines are shut down for cleanlike. ing and other repairs.

It is now proposed to utilize a. novel type of Auhou h it is o certain. it is l d a substanc a a film-forming material on the surit is the water-repellent characteristic of the face of the spinneret to inhibit the incrustation rgan -sili on a d s that Will Prevent inithereof over long periods of time, as it has been mize the contamination of the spinneret orifices. determined that such substance is suitable for Among the various organo-silicon halides that this use. These substances are of the class and character of those described in the U. S. Patent No. 2,306,222 in the name of Winton I. Patnode and assigned to General Electric Company.

This invention has for its purpose the applica- 2 tion of these substances, namel organo-sillcon halides, to the surface of the spinnerets and the use of the treated spinnerets in the production of rayon by the viscose process.

. are intended for treating spinnerets may be mentioned the alkyl silicon halides such as methyl, ethyl, propyl, and butyl chlorides or bromides, the aryl silicon halides such as phenyl silicon halides, aralkyl silicon halides such as phenyl- Means such as tolyl silicon halides, and similar alkyl,

aryl, etc., halosilanes such as chlorosilanes.

What is claimed is:

1. Incident to the manufacture of viscose rayon wherein a viscose solution is extruded through minute spinneret orifices into an acid spinbath to form threads and the like therefrom, a process of treating spinnerets having moisture adsorbed on the surface thereof, which comprises contacting the spinnerets with an organo-silicon halide to effect the reaction of the halide with the moisture and the resultant formation in situ of a very thin, substantially permanent, acid resistant, water repellent organo-silicone film on the surface of the spinnerets whereby contamination of the spinneret orifices during the spinning operation is inhibited.

2. Incident to the manufacture of viscose rayon wherein a viscose solution is extruded through minute spinneret orifices into an acid spinbath to form threads and the like therefrom, a process of treating spinnerets having moisture adsorbed on the surface thereof, which comprises contacting the spinnerets with a methyl silicon halide to eifect the reaction of the halide with the moisture and the resultant formation in situ of a very thin, substantially permanent, acid resistant, water repellent methyl silicone film on the surface of the spinnerets whereby contami= nation or the spinneret orifices during the spinning operation is inhibited.

4 3. In the manufacture of synthetic threads wherein a liquid is extruded through minute spinneret orifices to form filamentous threads REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,100,581 Weeldenburg Nov. 30, 1937 2,273,638 Graves et a]. Feb. 1'7, 1942 2,306,222 Patnode Dec. 22, 1942 OTHER REFERENCES Chem. a Mett. Eng, Aug. 1944, pp. 109, 135, 136.

Chemistry of the Silicones, by E. G. Rochow, pp. 62-82, John Wiley 8; Sons, Inc., N. Y., 1946. (Copy in Div. 6.) 

